Secretion of DNases by Marine Bacteria: A Culture Based and Bioinformatics Approach

Abstract

The vast majority of bacteria present in the natural environment are present in the form of aggregates and/or biofilms. Microbial aggregates are ubiquitous in the marine environment and are inhabited by diverse microbial communities which often express intense extracellular enzymatic activities. However, the secretion of an important group of enzymes, DNases, by bacteria from marine aggregates has not been studied, despite the importance of these aggregates in biogeochemical cycling of nutrients in the oceans. In this work, we therefore, employed both culture-based and bioinformatics approaches to understand the diversity of bacterial DNases in marine bacterioplankton. We found that 34% of 345 strains of attached and non-attached marine bacteria showed extracellular DNase activity. Most of these isolates belong to Proteobacteria (53%) and Firmicutes (34%). Secretion of DNases by bacteria isolated from marine gel particles (MGP) is reported here for the first time. Then, to further understand the wider diversity of the potential to produce DNases, sequences were compared using 2316 whole genome and 42 metagenome datasets. Thirty-nine different taxonomic groups corresponding to 10 bacterial phyla were found to encode genes responsible for DNase secretion. This study highlights the unexpected and widespread presence of DNase secretion in bacteria in general and in MGP more specifically. This has important implications for understanding the dynamics and fate of marine microbial aggregates in the oceans.

The effect of crop species on DNase-producing bacteria in two soils

“…Although we only identified six Bacillus species (B. cereus, B. muralis, B. mycoides, B. pumilus, B. simplex and B. thuringiensis) that produce exDNase, several other Bacillus species have been reported to exhibit extracellular nuclease activity including B. subtilis (Akrigg and Mandelstam 1978;Moreno et al 2012); B. licheniformis (Nijland et al 2010); B. fusiformis, B. megaterium, B. sphericus, B. brevis (Balestrazzi et al 2007); and B. seohaeanensis, B. stratosphericus, B. oceanisediminis, B. mojavensis (Moreno et al 2012). A study by Al-Wahaibi et al (2019) reported the Bacillus genera group to constitute the largest proportion of culturable exDNase-producing bacterial isolates from different marine habitats. However, their findings that Proteobacteria (57%) and Firmicutes (34%) dominated culturable exDNase-producing bacterial isolates contrasts our results as the largest proportion belonged to Firmicutes (54%) while Actinobacteria were the second largest group (20%).…”

Optimization of PhysicoChemical Parameters for Production of Cytotoxic Secondary Metabolites and Apoptosis Induction Activities in the Culture Extract of a Marine Algal–Derived Endophytic Fungus Aspergillus sp.

“…Most of these marine algal-derived fungi grow in an exceptionally extreme and inimitable habitat, which makes them capable to produce unusual secondary metabolites. This is simply because of their existence and adaptation to a distinct ecosystem (Flewelling et al, 2015;Wahaibi et al, 2019). Several studies have previously demonstrated the cytotoxic activities of marine endophytic extracts in cancer cells (Kamat et al, 2020a;Kamat et al, 2020b;Sajna et al, 2020).…”

Fitness of Outer Membrane Vesicles From Komagataeibacter intermedius Is Altered Under the Impact of Simulated Mars-like Stressors Outside the International Space Station

“…Nucleases perform different roles to fit bacterial lifestyle ( Al-Wahaibi et al, 2019 ; Pressler et al, 2019 ). Extracellular nucleases are known as enzymes to accommodate invading bacteria in hosts via the formation of a set of diverse oligonucleotides with immunomodulatory properties ( Takahashi et al, 2006 ) or help evade the innate immune response ( Jhelum et al, 2018 ).…”